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Dec 15, 2010, 01:15 PM
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Guizzo 17's Avatar
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Build Log

Keil Kraft Avro 707


A couple of years ago I tried to build a Jetex model.
It was a Keil Kraft Attacker which, before painting, I balanced and than test-flew with a Jetex 50 motor. The attacker made a nice looping but ended a couple of meter lower than the starting point. You may see the result in pic 1!
This, and the toilsome preparation and maintenance of the jetex, ended my approach to jet propulsion.
Recently, a friend gave me another KK kit with an Avro 707 and I fancied that a rubber catapult could be a simpler way to fly the model.
Here is what I'm doing.
I'm used to work in more than one project at a time so do not expect I'll post very often.
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Dec 16, 2010, 01:07 AM
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TLyttle's Avatar
Nice work, Guizzo, looks really nice, and I know what you mean about building more than one project at a time.

However, when it comes to test flying, I cheat. I build a profile sheet model off the plans, and use it for trimming; that way there are few surprises when it comes time to fly your stick&tissue version. The last time I did this it was with an Avro Arrow (CF105), and I had so much fun with the profile that I never did build the proper scale one!
Dec 16, 2010, 01:07 PM
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Guizzo 17's Avatar
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Quote:
Originally Posted by TLyttle
when it comes to test flying, I build a profile sheet model off the plans, and use it for trimming; that way there are few surprises when it comes time to fly your stick&tissue version.
I'm not old enough to be so wise!
Dec 18, 2010, 12:22 AM
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TLyttle's Avatar
Oh, I'm old alright, and I DID learn by making all the mistakes. My early days of catapult/towline/Jetex experimentation littered the landscape with my learning experiences. There is nothing like watching one's Cleveland kit (man, they were expensive back then!) reduce itself to rubbish because of inexperience and over-eagerness. Too soon old, too late smart, they say...
Jan 02, 2011, 12:07 PM
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Guizzo 17's Avatar
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Something more done!
Mar 23, 2011, 04:24 PM
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Guizzo 17's Avatar
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At last I finished the wing!
I made them detachable since it is the most rapid method for setting the right amount of dihedral.
This method do not add much weight to the structure and, hopefully, will even make future repairs easier.
You may also see that I doubled the number of wing ribs shown in the plan.
The spar is a 2mm carbon rod and where it meets the ribs, these are reinforced with a disk of 0.6mm plywood.
Just to save a bit of weight (!!!) I built the fin using sticks instead of balsa sheet.
The tail cone is paper and the piece of balsa protruding from it is the "jet plume" that will serve for grasping the model during launch.
Mar 23, 2011, 05:04 PM
Vertically Challenged...
Cody's Neighbour's Avatar
Nice job Guizzo17!

Should look really good when it's covered.
Mar 23, 2011, 06:10 PM
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Nice work!

Could you post some pictures of the tube structures in the wings? Is that just for strength, or is it part of the wing mounting?
Mar 28, 2011, 07:37 AM
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Guizzo 17's Avatar
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Thanks mates!
56Seeker, the structure is part of the wing mounting. As you may see from the first picture on post #6, I'm building the model in three separate pieces which are connected by the 2mm carbon rod spar.
There are no tubes; the spar goes through the fuselage sides and enters with a slight friction into the reinforced holes I made to the first 3 ribs of both wings (pics 2 & 3 of post #6).
Close to the leading edge of the first rib (first pic on this post), I made a second hole and I glued a peg to keep the wing aligned.
The carbon rod spar determines also the amount of wing dihedral and that's the reason it is so close to the extrados of the rib.
I trust on the friction between carbon rod spar and the holes in the wing ribs to keep the model together.
In the chance it is not enough, Iíll add small magnets.
I hope I made myself understood!


Yesterday I found the time to cover the wings.
This is just the second time I'm using esaky and I didn't know it shrinks so little when applied dry.
As you may see from the pictures the result is unacceptable and I need to do all over again.
Mar 28, 2011, 02:48 PM
Vertically Challenged...
Cody's Neighbour's Avatar

Esaki Covering


Guizzo17

Don't let it get you down mate. For me Esaki is best put on wet, or at least damp. If you give the airframe a couple of coats of full strength dope (sand it in between). Then put the Esaki on wet (I spray it with a hand sprayer) gently pull it tight and brush thinners around the edge. Rub it down with your fingers. Leave it to dry overnight before doping it with 50-50 or 60-40 thinners and dope. It'll come out good bro!

Bert
Jul 29, 2011, 08:56 AM
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Guizzo 17's Avatar
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At last my model is complited! It took me a while but during the good season I fly, and the time I spend in my workshop is mainly devoted to repair, fix and set the models I fly.

I even like to work in more than one project at the same time and while I was working on the Avro, I was even completing my last Tomboy, a small electric F/F and an enlarged R/C version of the Little Bug.

As you may see, I re-covered the entire wing and, following the suggestions Bert gave me on the previous post, I applied the Esaky tissue wet and gave two light coats of dope. No wrinkles this time! Thanks Bert!

I admit that I completely failed coosing the color of the covering! The original aircraft was orange and not amaranthine.

I made my own decals which I post on the off chance someone needs them.

The model weights 25 grams including a whit of ballast and the first hand launches look promising. I hope to start the first catapult launches in short-term.
Jul 29, 2011, 07:09 PM
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gossie's Avatar
Nice work Guizzo.
Jul 30, 2011, 01:50 AM
Vertically Challenged...
Cody's Neighbour's Avatar
Lovely job Guizzo - I like the colour!

Bert
Jul 30, 2011, 01:15 PM
Registered User

Avro


Excellent workmanship/ job well done. I like look of good tissue job. Detail work is fine. Best to you with test flights.
Cheers,Dan
May 20, 2021, 02:54 AM
Delusional Wanna-Be
John Rood's Avatar
Quote:
Originally Posted by Guizzo 17
...I completely failed choosing the color of the covering! The original aircraft was orange and not amaranthine. ...
Actually, your red color choice is accurate for WD280. And attractive! Great job on your beautiful model.


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